This invention relates to spools for wire, and more particularly to tapered flange wire spools having outwardly flared end flanges at opposite ends of a barrel.
Tapered flange wire spools now in general use are commonly made from synthetic plastic resins because of their relatively low weight and cost. Such plastic spools loaded with wire are ordinarily shipped in cartons with the longitudinal axis of the spools disposed vertically. Because a substantial weight of wire usually in excess of ten kilograms is carried by each spool, the lower weight supporting end flanges of the spools tend to break, crack, or split when subject to shock and impact forces during shipment. The upper end flanges are likewise subject to damage when the spools are disposed beneath other objects such as additional spool containing cartons. As shown in U.S. Pat. No. 3,717,315, tapered flange wire spools can be made more rugged by employing a relatively thick-wall construction of fiberglass and polyester resin materials and reinforcing the peripheral bead portion of each end flange with a wire ring insert. Although this spool construction is more resistant to damage, its cost is greater than that of an unreinforced thin-wall spool construction.
In plastic spools having generally planar end flanges normal to the spool axis, it is known to provide each end flange with an axially outwardly extending annular rim at its outer periphery joined to the outer surface of the end flange by radial ribs. Examples of this type of end flange construction are disclosed in U.S. Pat. Nos. 3,822,841 and 3,948,458. It is evident that the incorporation of this type of flange construction in tapered flange spools would increase the complexity and cost of the spools with only a minimum improvement in resistance to shock and impact forces.